The present invention relates to an unwinding apparatus for reeling off coiled material such as cables or annular pipes or similar winding goods, such as plastic tubes (used, e.g., for installation of water pipelines or heating pipelines), that have been wound to annular coils.
Electric cables or pipes, for example for a floor heating system, are oftentimes very long, e.g. of 50 m to 750 m, and thus wound into annular coils. Typically, the coiled material has a hardness that allows elastic bending. Not only because of their extensive length but also because of their great weight, these coils are difficult to handle. Thus, unwinding devices are used for processing the annular coils and are made available in various diameter, height and weight. Unwinding devices typically include a base constructed to resemble a cross or spoke wheel and a coil holding device which is rotatably connected to the base and on which the annular coils are loaded. Clamping elements project from the coil holding device for tensioning and centering the annular coils on the coil holding device.
Unwinding devices with a rotation axis aligned in vertical direction to the standing area as well as winding devices with a rotation axis aligned in horizontal direction (German utility model no. 7830957) have been used. The coils are reeled off from a coil holding device manually, whereby the coiled material rotates in unison with the coil holding device about an axis.
A drawback of prior art unwinding devices is their limited use to accommodate annular coils of different inner and outer diameters, different heights and different weights, and their bulky and heavy construction that requires large spaces for their transport and storage.
As they are paid out, the weight of the annular coils is subjected to centrifugal forces that cause the coil to continue to rotate, even though a stoppage is intended. As a result, the length of unwound material is longer than desired so that a portion of material dangles from the coil holding device and may get entangled in the apparatus. Thus, the subsequent unwinding operation becomes more difficult so that a continuous supervision is required which unnecessarily prolongs the process and renders a desired remote-controlled operation of the unwinding apparatus difficult to implement. Prior art unwinding apparatuses lack also sufficient stability and may tilt so that the coils may get jammed, thereby adversely affecting a further unwinding operation. In a worst case scenario, the unwinding apparatus including the annular coil may even topple over, requiring the operator to intervene, thereby further complicating and prolonging installation of the winding material.
It would therefore be desirable and advantageous to provide an improved unwinding apparatus to obviate prior art shortcomings and to allow universal application while still being easy to transport and reliable in operation.